Lubricating oil compositions



United Sttes 2,816,868 LUBRICATING OIL COMPOSITIONS No Drawing. Application March21,.19'55 Serial No. 495,758

4 Claims. (Cl. 252-42.7)

The present invention relates to compounded lubricating oil compositions which are particularly suitable for use in engines operating with diesel fuels. 7

Diesel fuels, because of their complex hydrocarbon structure, have a greater tendency toward soot and resin formation than do fuels used in spark ignition engines, resulting in more piston varnish and ring sticking problems. In addition, higher operating temperatures are used so that more severe demands are imposed by diesel engines upon the lubricating oil.

It has now been discovered that an excellent lubricating oil base suitable for use in diesel engines operating on various diesel fuels such as used in railroad, truck, bus and other types of diesel engines, and adaptable for compounding with various additives, e. g., dispersants or detergents, can be obtained by fractionating mineral oil, such as a distillate fraction, as by extraction, adsorption, acid washing, etc., and then reblending specific proportions of certain of the components which are present in the base oil stock. These blends consist essentially of a mixture of (1) from about 60% to 95% of predominantly saturated paratfinic lubricating oil distillate components, which generally are non-straight chain paraflinic hydrocarbons, preferably being a saturate fraction consisting essentially of naphthenic hydrocarbons of one or more rings and up to about 20% isoparafiinic hydrocarbons, and (2) from about to about 40% of polyaromatic hydrocarbons containing two or more aromatic nuclei such as diaromatic hydrocarbon fractions containing co-fused therewith naphthenic rings, and preferably such substances as alkyl naphthenonaphthalenes. These polyaromatic fractions contain alkyl radicals attached to either or both the aromatic and/ or naphthenic rings.

The two fractions which constitute the novel lubricating oil base of this invention can be obtained from various types of lubricating oil stocks, such as distillate lubricating oils from California, Texas, Oklahoma, Mid-Continent, Pennsylvania, Near East, or Gulf Coast crudes. The essential fractions can be obtained by treating a suitable lubricating oil distillate with solid adsorbents, such as silica gel, alumina, activated carbon, and the like, and/or with one or more of the well-known selective solvents, such as phenols, furfural, sulfur dioxide, ketones, nitro benzene, and the like. The most effective method of treating (fractionating) the lubricating oil is by adsorptive separation with silica gel, e. g., by the methods described in U. S. Patents 2,674,568 or 2,643,217.

Particularly suitable base oil stocks (for treatment with solid adsorbents, such as silica or silica-alumina gels to obtain the separate defined fractions which, when blended, produce the final lubricating oil product of this invention) include lubricating oil distillates, such as from East Texas, West Texas Ellenburger and Ventura petroleum crudes, having a boiling range at about one atmosphere pressure within the temperature range of from about 400 C. to about 750 C., and preferably from about 450 C. to about 600 C.

, The desorbing agents which can be used todisp'lace the atent various hydrocarboncomponents from the solid adsorbent in the adsorptive separation process should be solvents which have complete miscibility with the charge stock at all concentrations. When distillation is to be used to remove the desorbing agent from the product, it should have a boilingpoint substantially different from the charge components to permit ready separation. The desorbing agent used is preferably a low molecular weight saturated non-aromatic hydrocarbon having from about 3 to about 10 carbon atoms per molecule. Suitable desorbing agents include the alkanes and cycloalkanes, such as isopentane, isobutane, hexane, heptane, cyclopentane, cyclohexane, and the like, as well as their isomers, and various mixtures thereof, such as petroleum ether.

In the adsorption process, either a batch or continuous technique can be used. In a batch process, the lubricating oil fraction to be treated is introduced into a stationary column of the solid adsorbent until the capacity of the solid adsorbent for adsorbing further portions of lubricating: oilis' exhausted. The desorbing agent is then passed through the solid adsorbent containing the oil adsorbed thereon to selectively desorb the various fractions in succession. After the desired saturates and aromatics have been collected, separate from the undesirable fractions, the solid adsorbent is further treated with the desorbing agent to displace the remaining components. The solid adsorbent can then be reused for treating further portions of" the lubricating oil. It is preferred to subject the solid adsorbent, after the desorption operation, to steaming to remove any residual organic material. In a continuous process, the adsorbent is suitably utilized in the form of a moving bed. The adsorbent is introduced into the adsorption zone and is passed therethrough in the form of a moving bed. A stream of lubricating oil is continuously fed to the adsorption zone. The adsorbent, containing the lubricating oil substantially completely adsorbed thereon, is then introduced into a desorption zone and therein treated with a suitable desorbing agent to displace successively the various components of the oil. The desirable saturates and aromatics are collected and blended in suitable proportions, and the undesirable fractions are rejected. The treated solid adsorbent is then returned to the adsorption zone.- The desorbed components are suitably separated from the desorbing agent, as by distillation. The process is generally carried out at ambient atmospheric temperatures.

The following examples illustrate methods of producing compositions of this invention.

EXAMPLE I An East Texas lubricating oil distillate having a viscosity of about SSU at F. was substantially completely adsorbed on silica gel, the gel-to-oil ratio being about 8:1. The adsorbent was then treated with isopentane to desorb successive fractions of saturated and aromatic hydrocarbons. The isopentane was removed from each of the fractions by distillation. Oil fractions so produced comprised: (1) about 60% of a saturate fraction (containing about 20% isoparaffins and about 80% alkyl naphthenes of l to 5 rings and averaging 2 rings), (2) about 20% monoaromatics, and (3) about 20% of a polyaromatic fraction containing about 10% naphthenonaphthalenes, with the balance being essentially all alkyl phenanthrenes, naphtheno-phenanthrenes and chrysenes. The composition of the saturate fraction and of the aromatic fraction was determined by mass spectrometry and ultraviolet spectrometry (Friedel- Orchin, Ultraviolet Spectra of Aromatic Compounds," John Wiley and Sons). An oil composition (A) of the invention was prepared by blending about 80% by weight of saturates fraction (1) with about 20% by weight of polyaroma'tics fraction (3),. i

- 2,441,258 and 2,488,721. can be utilized in compositions of this invention include 3 EXAMPLE II A West Texas Ellenburger lubricating oil distillate having a viscosity of about 135 SSU at 130 F. was substantially completely adsorbed on silica gel, the gel-to-oil ratio being about 8:1. The adsorbent was then treated with isopentane to desorb successive fractions of saturated and aromatic fractions. The isopentane was removed from each of the fractions by distillation. Oil fractions so produced comprised: (1) about 60% of a saturate fraction containing about 15% isoparaflins and about 85% alkylnaphthenes of 1 to 4 rings and averaging 2 rings, (2) about 20% monoaromatics, and (3) about 20% of of a polyaromatic fraction consisting essentially of naphthenonaphthalenes, phenanthrenes, naphtheno-phenanthrenes and chrysenes.

An oil composition (B) of the invention was prepared by blending about 80% by weight of the saturates fraction (1) and about 20% by weight of the polyaromatics fraction (3).

If desired the saturates-polyaromatics blend of this invention can be further improved with respect to stability, lacquer prevention and other properties by addition thereto of from about 3% to about 25% by weight of a bright stock fraction containing a substantial amount of alkyl naphthalenes and having a molecular weight range of from about 750 to about 1000. If desired a broader fraction can be used and which contains in addition to alkyl naphthalenes other hydrocarbons such as saturates, monoand polyaromatics but having a molecular weight of at least 700. The term bright stock" refers to a residue lubricating oil fractions as defined in standard texts on the subject as Motor Oils and Engine Lubrication, by Georgi. Thus, foregoing compositions A and B can be still further improved by addition of i from about 3% to about 25% by weight of a bright stock alkylnaphthalene fraction having a molecular weight greater than 700 and preferably in the molecular weight range of from about 750 to about 1000. Such compositions are illustrated by:

' Composition C:

Lubricating oil compositions of this invention are parr ticularly suitable for use with dispersant or detergent additives. Such compounds include oil-soluble salts (metal or non-metal) of organic acidic compounds or 1 inorganic acids containing organic radicals such as alkali,

alkaline earth and heavy metal salts of oil-soluble carboxylic acids, e. g. naphthenic acids, sulfonic acids, car- 'bamic acids, phenolic compounds, organic acid phosphates, phosphonic acids and the thio analogues of said acidic compounds. Preferred are the oil-soluble polyvalent metal sulfonates and phenates such as the Ca, Ba,

' Mg, Al, Zn and Pb petroleum sulfonates, naphthenates and alkyl phenates.

The sulfonates for use in compositions of this invention include petroleum sulfonates described in U. S. Patents 2,280,419, 2,344,988, 2,361,804, 2,375,222, 2,480,638 2,485,861, 2,509,863, 2,501,731, 2,523,582,

and 2,585,520. If desired, the sulfonates can be purified by the methods described in United States Patents The aromatic sulfonates which those described in United States Patents 2,411,583, 2,418,894, 2,442,915, 2,483,501, 2,531,325, 2,556,198 and 2,556,848. Although various metal sulfonates are contemplated in the practice of the invention, including alkali metal sulfonates, alkaline earth metal sulfonates (including magnesium) and other polyvalent metal sulfonates, particularly other divalent metal sulfonates and trivalent metal (neutral for basic) sulfonates, the sulfonates of the metals of group II of the periodic table and having an atomic number from 12 to 56 are preferred, and especially of the alkaline earth metals within that group of metals. Specific sulfonates which are particularly suitable for use in compositions of this invention include oil-soluble metal sulfonates such as Na, K, Li, Ca, Ba, Mg, Sr, Al, Zn, Sn, Cr, and Co petroleum sulfonates, tetra-tertiarybutylnaphthalene sulfonates, diwaxbenzene sulfonate, stearylbenzene sulfonate, diwaxnaphthalene sulfonate, diisobutylenephenol sulfonate, tertiaryoctylphenol sulfonate, ditertiaryamylphenol sulfonate, alkylated dibenzothiophene sulfonate and mixtures thereof.

In order to demonstrate the efficiency of lubricants of the present invention to maintain engine cleanliness during operation thereof, and'by comparison to show the marked superiority of the present compositions over lubricants comprising essentially only the saturates fraction, with added detergent, various Lauson engine tests were made using a straight run fuel and operating under temperature conditions approximating those of normal diesel engine operations. The results are tabulated in Table I.

Table I Composition Composition E:

99% wt. Saturates-Polyaromatics blend consisting Saturates (Ex. II) 20% Polyaromatics (Ex. II) 1% wt. Ca salt of Octyiphenol-iormaldehyde condensation product Composition X:

99% wt. SaturatesMonoai-omatics blend consisting of- 80% saturates (Ex. 1') 20% Monoaromatics (Ex. I) 1% wt. Ca salt of Octylpheno ormaldehyde condensation product Composition XX:

99% wt. saturates (Ex. II) 1% wt. Ca salt of Octylphenol-iormaldehyde condensation product Compositions A and B were tested in the Lauson engine for bearing corrosion and gave a value of about 15:10 mg. whereas composition Y (80% saturates of Example I+20% monoaromatics of Example 1), composition YY 80% saturates of Example I I+20% monoaromatics of Example II), composition Z (saturate fraction of Example I) and composition ZZ (saturate fraction of Example 'II) resulted in bearing weight losses of from 670 to 1200 mg.

Composition E of this invention was tested in the Fairbanks-Morse diesel engine under the following conditions: speed, 1200 R. P. M., load 8 H. P., test time, 40 hours, oil temperature, C., jacket temperature, 100 C., and no abnormal ring wear was noted and the engine was in excellent condition at the end of the test.

Compositions of this invention can be modified as desired by addition thereto of minor amounts (1-2%) of pour point depressants, viscosity index improvers, blooming agents, corrosion inhibitors, oiliness agents, solubilizers, and the like. Among such materials are molecular weight polymers, e. g., acryloids," which are polymeric esters of methacrylic acid and coconut fatty alcohols, wax-naphthalene condensation products, isobutylene polymers, alkylstyrene polymers; inorganic and organic nitrates such as NaNO or LiNO and diisopropylarnmonium nitrate or dicyclohexylammonium nitrite, organic sulfides, e. g., wax disulfide, bisethylenetolyl sulfide, amines, e. g., octadecylamine and the like. Also, phenolic antioxidants such as 2,6-ditertiarybutyl-4-methyl phenol and 2,2-methylene bis(4-methyl-6-tertiarybutylphenol) can be used in conjunction with the additive combination of this invention.

We claim as our invention:

1. A mineral lubricating oil composition consisting essentially of a major amount of a mineral lubricating oil containing (1) from about 60% to about 95% of a mixture of saturated hydrocarbons of lubricating viscosity consisting of up to 20% isoparaflins and the balance being naphthenes and (2) from about 5% to about 40% of a mixture of mineral oil polyaromatic hydrocarbons consisting of from 2 to 3 aromatic nuclei and co-fused naphthene rings, essentially free from other types of components of mineral lubricating oils, said fractions (1) and (2) being separated from mineral lubricating oil and from about 0.01 to about of an oil-soluble alkaline earth metal phenate.

2. A mineral lubricating oil composition consisting essentially of a major amount of a mineral lubricating oil containing (1) from about 60% to about 95% of a mixture of saturated hydrocarbons of lubricating viscosity consisting of up to 20% isoparafiins and the balance being naphthenes and (2) from about 5% to about 40% of a mixture of mineral oil diaromatic hydrocarbons separated from a mineral lubricating oil fraction, said fractions 1) and (2) being essentially free from other types of components of mineral lubricating oil and from about 0.01 to about 10% of an oil-soluble alkaline earth metal phenate.

3. A mineral lubricating oil composition consisting essentially of a major amount of mineral oil containing (1) from about 60% to about 95% of a mixture of saturated hydrocarbons of lubricating viscosity consisting of up to 20% isoparatfins and the balance being naphthenes and (2) from about 5% to about of a mixture of mineral oil diaromatic hydrocarbons containing co-fused naphthene rings separated from a mineral lubricating oil fraction, said fractions (1) and (2) being essentially free from other types of components of mineral lubricating oil and from about 0.01 to about 10% of calcium salt of octylphenol-formaldehyde condensation product.

4. A mineral lubricating oil composition consisting essentially of a major amount of mineral oil containing about of saturated hydrocarbons of lubricating viscosity consisting of up to 15% isoparaffins and about alkyl naphthalenes of 1 to 4 rings and averaging 2 rings and (2) from about 5% to about 40% of alkyl naphthalenes, said fractions 1) and (2) being separated from a mineral lubricating oil and essentially free from other types of components of mineral lubricating oil and about 1% of calcium salt of octylphenol-formaldehyde condensation product.

References Cited in the file of this patent UNITED STATES PATENTS 2,247,475 Bray et a1. July 1, 1941 2,606,372 Gasser et a1 Aug. 12, 1952 2,671,758 Vinograd et al. Mar. 9, 1954 2,674,568 Lillard Apr. 6, 1954 2,754,254 Hastings et a1. July 19, 1956 2,756,197 Thorpe et al. July 24, 1956 2,767,131 Jezl et al Oct. 16, 1956 2,768,128 Knox Oct. 23, 1956 OTHER REFERENCES Motors Oils, by Georgi, Reinhold Pub. Co. N. Y., 1950, pages 109, 122, 138 and 139 pertinent. 

1. A MINERAL LUBRICATING OIL COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR AMOUNT OF A MINERAL LUBRICATING OIL CONTAINING (1) FROM ABOUT 60% TO ABOUT 95% OF A MIXTURE OF SATURATED HYDROCARBONS OF LUBRICATING VISCOSITY CONSISTING OF UP TO 20% ISOPARAFFINS AND THE BALANCE BEING NAPHTHENES AND (2) FROM ABOUT 5% TO ABOUT 40% OF A MIXTURE OF MINERAL OIL POLYAROMATIC HYDROCARBONS CONSISTING OF FROM 2 TO 3 AROMATIC NUCLEI AND CO-FUSED NAPHTHENE RINGS, ESSENTIALLY FREE FROM OTHER TYPES OF COMPONENTS OF MINERAL LUBRICATING OILS, SAID FRACTIONS (1) AND (2) BEING SEPARATED FROM MINERAL LUBRICATING OIL AND FROM ABOUT 0.01 TO ABOUT 10% OF AN OIL-SOLUBLE ALKALINE EARTH METAL PHENATE. 